Rotary Electric Machine Control Using Interpolation Angle Modulation
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Solution Overview
Problem
Existing rotary electric machine control devices struggle to achieve planned output characteristics due to transient phenomena, leading to suboptimal waveform design, especially in low-speed rotation regions, and require expensive high-resolution position sensors for improved controllability.
Innovation Solution
A control device and method that utilize a plurality of rotation angle sensors to calculate interpolation angles and determine modulation amounts based on induced voltage, generating driving waveforms through pulse modulation, while simplifying the circuit configuration and reducing costs by using a modulation amount map stored in a nonvolatile memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plurality of Hall sensors are used to interpolate magnetic pole positions, then angular resolution is improved, but transient phenomena cause the planned sinusoidal output waveform to cannot be obtained
Solution Approach 1:
The patent changes the control parameter from simple interpolated angle to angle-corrected modulation amount. By pre-calculating and storing the relationship between interpolation angles and optimal modulation amounts in a lookup table, the system compensates for transient phenomena and achieves accurate sinusoidal output waveforms without requiring expensive high-resolution position sensors.
2Ease of operation
If high-resolution position sensors are adopted to improve controllability, then output characteristics can be designed as planned, but device complexity and cost increase
Solution Approach 1:
The patent replaces expensive high-resolution position sensors with inexpensive Hall sensors combined with a software-based angle interpolation and modulation amount determination system. The lookup table stored in memory provides the functionality of high-resolution sensing without the cost and complexity of specialized sensors, achieving the same controllability improvement at lower device cost.
3Manufacturing precision
If high-resolution position sensors are used to improve output waveform design, then planned output characteristics can be achieved, but device cost increases
Solution Approach 1:
The patent creates a virtual high-resolution position sensor system by interpolating angles from multiple Hall sensors and using pre-calculated modulation amount lookup tables. This software-based copy of high-resolution sensing functionality achieves the same output waveform precision as physical high-resolution sensors would provide, but without the associated cost and complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the design of output characteristics as planned, enhancing controllability of rotary electric machines without the need for expensive high-resolution position sensors, thereby improving responsiveness and positional accuracy while reducing device complexity and cost.
Implementation Method 1
a plurality of rotation angle sensors fixedly disposed along the rotational direction of the rotary electric machine and configured to output detection signals in accordance with the angle of rotation of the rotary electric machine
Implementation Method 2
a driving waveform generating unit configured to generate the driving waveform by performing pulse modulation by the amount of modulation determined by the modulation amount determining unit
Data Source
AI summary
A motor control device performs rotation control of a motor by supplying a driving waveform to an inverter circuit. The motor control device determines the amount of modulation in accordance with an induced voltage of the motor based on a calculated interpolation angle, and generates the driving waveform by performing pulse modulation by this amount of modulation.